HBO1-MLL interaction promotes AF4/ENL/P-TEFb-mediated leukemogenesis

白血病を引き起こすタンパク質間相互作用の発見. 京都大学プレスリリース. 2021-08-31.Leukemic oncoproteins cause uncontrolled self-renewal of hematopoietic progenitors by aberrant gene activation, eventually causing leukemia. However, the molecular mechanism underlying aberrant gene activation remains elusive. Here, we showed that leukemic MLL fusion proteins associate with the HBO1 histone acetyltransferase (HAT) complex through their trithorax homology domain 2 (THD2) in various human cell lines. MLL proteins associated with the HBO1 complex through multiple contacts mediated mainly by the ING4/5 and PHF16 subunits in a chromatin-bound context where histone H3 lysine 4 tri-methylation marks were present. Of the many MLL fusions, MLL-ELL particularly depended on the THD2-mediated association with the HBO1 complex for leukemic transformation. The C-terminal portion of ELL provided a binding platform for multiple factors including AF4, EAF1, and p53. MLL-ELL activated gene expression in murine hematopoietic progenitors by loading an AF4/ENL/P-TEFb (AEP) complex onto the target promoters wherein the HBO1 complex promoted the association with AEP complex over EAF1 and p53. Moreover, the NUP98-HBO1 fusion protein exerted its oncogenic properties via interaction with MLL but not its intrinsic HAT activity. Thus, the interaction between the HBO1 complex and MLL is an important nexus in leukemic transformation, which may serve as a therapeutic target for drug development

Tomato root-associated Sphingobium harbors genes for catabolizing toxic steroidal glycoalkaloids

トマト根に定着する細菌からトマトの毒を分解する酵素を発見 --土壌微生物が植物の分泌する有害成分を解毒するメカニズムの理解に貢献--. 京都大学プレスリリース. 2023-10-02.Roots of Bloody Mary. Tomato root-associated Sphingobium harbors genes for neutralizing toxic compound. 京都大学プレスリリース. 2023-10-06.Plant roots exude various organic compounds, including plant specialized metabolites (PSMs), into the rhizosphere. The secreted PSMs enrich specific microbial taxa to shape the rhizosphere microbiome, which is crucial for the healthy growth of the host plants. PSMs often exhibit biological activities; in turn, some microorganisms possess the capability to either resist or detoxify them. Saponins are structurally diverse triterpene-type PSMs that are mainly produced by angiosperms. They are generally considered as plant defense compounds. We have revealed that α-tomatine, a steroid-type saponin secreted from tomato (Solanum lycopersicum) roots, increases the abundance of Sphingobium bacteria. To elucidate the mechanisms underlying the α-tomatine-mediated enrichment of Sphingobium, we isolated Sphingobium spp. from tomato roots and characterized their saponin-catabolizing abilities. We obtained the whole-genome sequence of Sphingobium sp. RC1, which degrades steroid-type saponins but not oleanane-type ones, and performed a gene cluster analysis together with a transcriptome analysis of α-tomatine degradation. The in vitro characterization of candidate genes identified six enzymes that hydrolyzed the different sugar moieties of steroid-type saponins at different positions. In addition, the enzymes involved in the early steps of the degradation of sapogenins (i.e., aglycones of saponins) were identified, suggesting that orthologs of the known bacterial steroid catabolic enzymes can metabolize sapogenins. Furthermore, a comparative genomic analysis revealed that the saponin-degrading enzymes were present exclusively in certain strains of Sphingobium spp., most of which were isolated from tomato roots or α-tomatine-treated soil. Taken together, these results suggest a catabolic pathway for highly bioactive steroid-type saponins in the rhizosphere

Pharmacologic characterization of TBP1901, a prodrug form of aglycone curcumin, and CRISPR-Cas9 screen for therapeutic targets of aglycone curcumin

プロドラッグ型クルクミン注射製剤の抗腫瘍効果及び治療標的の包括的な解析 --安全性の高い抗がん薬としての開発に期待--. 京都大学プレスリリース. 2022-10-21.Curcumin (aglycone curcumin) has antitumor properties in a variety of malignancies via the alteration of multiple cancer-related biological pathways; however, its clinical application has been hampered due to its poor bioavailability. To overcome this limitation, we have developed a synthesized curcumin β-D-glucuronide sodium salt (TBP1901), a prodrug form of aglycone curcumin. In this study, we aimed to clarify the pharmacologic characteristics of TBP1901. In β-glucuronidase (GUSB)-proficient mice, both curcumin β-D-glucuronide and its active metabolite, aglycone curcumin, were detected in the blood after TBP1901 injection, whereas only curcumin β-D-glucuronide was detected in GUSB-impaired mice, suggesting that GUSB plays a pivotal role in the conversion of TBP1901 into aglycone curcumin in vivo. TBP1901 itself had minimal antitumor effects in vitro, whereas it demonstrated significant antitumor effects in vivo. Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screen disclosed the genes associated with NF-κB signaling pathway and mitochondria were among the highest hit. In vitro, aglycone curcumin inhibited NF-kappa B signaling pathways whereas it caused production of reactive oxygen species (ROS). ROS scavenger, N-acetyl-L-cysteine, partially reversed antitumor effects of aglycone curcumin. In summary, TBP1901 can exert antitumor effects as a prodrug of aglycone curcumin through GUSB-dependent activation

Cooperative gene activation by AF4 and DOT1L drives MLL-rearranged leukemia

The eleven-nineteen leukemia (ENL) protein family, composed of ENL and AF9, is a common component of 3 transcriptional modulators: AF4-ENL-P-TEFb complex (AEP), DOT1L-AF10-ENL complex (referred to as the DOT1L complex) and polycomb-repressive complex 1 (PRC1). Each complex associates with chromatin via distinct mechanisms, conferring different transcriptional properties including activation, maintenance, and repression. The mixed-lineage leukemia (MLL) gene often fuses with ENL and AF10 family genes in leukemia. However, the functional interrelationship among those 3 complexes in leukemic transformation remains largely elusive. Here, we have shown that MLL-ENL and MLL-AF10 constitutively activate transcription by aberrantly inducing both AEP-dependent transcriptional activation and DOT1L-dependent transcriptional maintenance, mostly in the absence of PRC1, to fully transform hematopoietic progenitors. These results reveal a cooperative transcriptional activation mechanism of AEP and DOT1L and suggest a molecular rationale for the simultaneous inhibition of the MLL fusion-AF4 complex and DOT1L for more effective treatment of MLL-rearranged leukemia

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

Evaluation of a graphite calorimeter for measuring absorbed dose in heavy-ion beams

The World Congree on Medical Physics and Biomedical Engineering 200

Development of a Portable Graphite Calorimeter for Radiation Dosimetry

Abstract We developed and performance-tested a portable graphite calorimeter designed to measure the absolute dosimetry of various beams including heavy-ion beams, using a flexible and convenient means of measurement. This measurement system is fully remote-controlled by GPIB systems. The control system uses digital PID (Proportional, Integral, Derivative) control methods based on a LabVIEW program1). It was possible to attain stable conditions in a shorter time by this system. The standard deviation of the measurements using the calorimeter was 0.79 % at a dose rate of 0.8 Gy/min in seventeen calorimeter runs of a 60Co photon beam. The overall uncertainty for the absorbed dose to graphite and water of a 60Co photon beam using the developed calorimeter was 0.89 % and 1.35 %, respectively. Estimations of the correction factors due to vacuum gaps, impurities in the core, the dose gradient and the radiation profile were included in the uncertainty. The absorbed doses to graphite and water irradiated by a 60Co photon beam were compared with dosimetry using ionization chambers. The absorbed doses to graphite and water estimated by the two dosimetry methods agreed within 0.1 % and 0.3 %, respectively

Graphite Calorimetry for absdorbed dose measurements in heavy-ion beams

Graphite calorimetry for absorbed dose measurements in heavy-ion beamsM.Sakama(1)T.Kanai(1.2)A.Fukumura(2)(1)Tokyo Institute of Technology,Japan(2)National Institute of Radiological Sciences,Japan([email protected]/Phone:+91-43-251-2111)\nIn order to sophisticate the radiotherapy,high accuracy knowledge of the absorbed dose delivered to the patient is essential. The main methods of absolute doseimetryare indicated as follows;(a)Doseimetry by ion chamber(b)Fricke dosimetry and (c)Calorimetry. The calorimetry is most direct method of dosemetry due to direct measurement of energy deposit in principle and no requirement of information of radiation fields for the calibration. Many countries tend to adopt the calorimerty to determine the standard absorbed dose to water and become to be capable of deciding the absorbed dose in precision of about 0.6% for photon and electron beams. Despite the recent progress of particle therapy, the parameters such as w-value and stopping power ratio for ionization chambers in the particles is not obtained accurately. Therefore that causes uncertainty in determination of the absolute dose. For this reason, we developed a graphite calorimeter to obtain high precision absobed dose and reduce the uncertainty for various beams. When the absorbed dose of 1 Gy is irradiated to the senseitive volume, the temperature rise is abou 1.4 milliKelvins. The performance require the resolution of plus or minus 7 micro Kelvins to measure it in precision of plus or minus 0.5%. The stability within seberal micro Kelvins per minute is necessary to obtain measureable background.The miniature glass bead thermistors were embedded in the sensitive volume to perform active control of temperature. The resistance change of these themistors is approximately 0.68 Ohms and 488 micro Ohms at temperature rise of 1.4 milliKelvins and 1 micro Kelvins from 20 degrees, respectively. The temperature-measuring themistor is connected to a Wheatstone bridge and the resistance change is measured by lock-in amplifier and nanovoltmeter. Simulations and experiments have been performed for photon and various heavy-ion beams.Ｃｏｍｍｉｔｔｅｅ on Space Research 36th COSPAR Scientific Assembly 200